Pressure Piping Research Articles

A Hybrid Model for Freight Train Air Brake Condition Monitoring

The Digital Freight Train is expected to revolutionise the rail freight industry. A critical aspect of this transformation is real-time condition monitoring of air brake systems, which are among the leading causes of train malfunctions. To achieve this goal, advanced algorithms for air brake modelling are required. This paper introduces a computationally efficient air brake model tailored for real-time diagnostic applications. A hybrid approach, integrating both empirical data and simplified fluid-dynamic equations, has been adopted. Compared to other air brake models found in the literature, the innovative contributions of the presented model are the reduction of the number of required parameters and the estimation of the brake cylinder pressure directly from the main brake pipe pressure using a feed-forward approach. Moreover, a new approach in the evaluation of the first braking phase and the brake cylinder pressure build-up as the saturation of the brake mode is presented. The model input includes the main brake pipe pressure, the weighing valve pressure, and the brake mode, and the output includes the pressure at the brake cylinder. The air brake model has been validated using data from a previous experimental campaign. The model’s accuracy in replicating the air brake system mechanism makes it well-suited for future development of model-based algorithms designed for air brake fault detection.

Stability performance of pumped-storage units considering elastic water hammer effects in pressurized piping systems: Mechanism analysis and quantitative criterion

The flow characteristics of water columns in pressurized piping systems significantly influence the stability of pumped-storage power stations (PSPSs). However, the complex mathematical representation of the elastic water column often leads to its simplification to a rigid column in stability analyses. This study established elastic and rigid models of a PSPS system based on elastic and rigid water columns, respectively. The stability regions of the governor parameters for these two models were determined and compared. Results indicate that the stability region of the elastic model is smaller than that of the rigid model. Consequently, using a simplified rigid model to evaluate the stability of an actual elastic system would pose potential instability risks. Furthermore, the primary cause of the stability difference between the elastic and rigid models is identified as the water hammer wave velocity. As the wave velocity increases, the stability region of the elastic model expands, eventually approaching that of the rigid model. Lastly, the coupling mechanism between the pressurized pipe and the pumped-storage unit is clarified. The modulus of the water hammer reflection coefficient is proposed to quantify the stability performance of the pumped-storage unit. These findings provide crucial insights for ensuring the stable operation of PSPSs.

Mesh Sensitivity Analysis of Axisymmetric Models for Smooth–Turbulent Transient Flows

The current paper focuses on the assessment of radial mesh influence on the description of the transient event obtained by an axisymmetric model. The objective is to reduce computational effort while accurately calculating hydraulic transients in smooth–turbulent pressurized pipes. The analyzed pipe system has a reservoir–pipe–valve configuration with an inner diameter of 0.02 m and a total length of 14.96 m, with the initial discharge being equal to 120 × 10−3 L/s (Re = 7638). An extensive study is carried out with 80 geometric sequence meshes by varying the total number of cylinders, the geometric common ratio, and the pipe axial discretization. The benefit of increasing the geometric common ratio is highlighted. A detailed comparison between two meshes is presented, in which the best mesh (i.e., the one with the lowest computational effort) has a three-fold higher value of the geometric common ratio. The two meshes show small differences for the instantaneous valve closure, limited to a time interval immediately after the arrival of the pressure surge and only during the first pressure wave. The dynamic characterization of the transient phenomenon demonstrates the in-depth consistency between the model results and the hydraulic transients’ phenomenon in terms of the piezometric head, the wall shear stress, and the mean velocity time-history, in comparison to the results obtained with the shear stress, lateral velocity, and axial velocity profiles.

Experimental Investigation of Heat Pipe Flow Dynamics and Performance

Due to their safety, efficiency, and passive operation, heat pipes have found diverse applications that include nuclear microreactors. Heat pipes enable increased reliability in microreactors, as they eliminate the need for reactor coolant pumps and their associated auxiliary systems while resulting in a greatly reduced spatial footprint. Experimental work is needed to support and expedite the design and licensing of heat pipe microreactors, especially the validation of heat pipe performance, as key heat transfer components. The present work develops a comprehensive heat pipe experimental database covering a wide range of heat pipe operating conditions. In addition, two-phase thermosyphon experiments are conducted to serve as a benchmark for performance. The operating conditions are determined based on previously developed scaling laws for heat pipes and two-phase thermosyphons using low-temperature working fluids. The tested heat pipe is about 2 m long and equipped with in-house-developed annulus screen wicks. To allow for the investigation of heat pipe flow dynamics, various instruments are incorporated to acquire heat pipe pressures, pressure drops, and temperatures. In particular, a fiberoptic sensor is implemented to measure temperatures along the centerline of the entire heat pipe. The results can be directly applied to the advancement of numerical tools currently under development for heat pipe microreactor analysis.

Analytical Mini-Review of Different Sheet Pile Configuration Utilization for Dam Seepage Reduction and Applications on Iraqi Dams

Abstract Seepage is one of the main causes of dams and some other hydraulic structures' failure. Water movement beneath the dam’s base creates piping and uplift pressure under the structure, potentially leading to improper dam operation. This current study focuses on the utilization of a special technique to restrict the transfer of movement water via soil which includes sheet piles under the dam foundation. Sheet pile walls are interlocking pile segments that are embedded in soil to resist horizontal pressure, classified as a flexible retaining system, and capable of tolerating relatively large deformations. Sheet piles are made of various materials, such as wood, concrete, steel, and aluminum, which are suitable for different applications. The role of seepage can be affected by the cutoff utilization. In this study, some Iraqi dam issues due to seepage are explained, also the geological stratum beneath the dam is briefly discussed. the potential use of sheet piles with different configurations has been reviewed to detect the optimum situation for seepage parameters reduction based on their numbers, interval distances, inclinations, and places. Keywords: Seepage, sheet piles, impermeable foundation, Iraqi dams’ issues, and geological stratum.

Towards resilient pipeline infrastructure: lessons learned from failure analysis

Understanding the mechanisms of pipeline failures is crucial for identifying vulnerabilities in gas transmission pipelines and planning strategies to enhance the reliability and resilience of energy supply chains. Existing studies and the American Society of Mechanical Engineers’ (ASME) Code for Pressure Piping primarily focus on corrosion, recommending inspections every 10 years to prevent incidents due to this time-dependent threat. However, these guidelines do not provide comprehensive regulation on the likelihood of incidents due to other causes, especially non-time-dependent events (i.e. do not provide any indication of the inspection frequency or the most likely time for an incident to occur). This study adopts an innovative approach adopting machine learning, particularly artificial neural networks (ANNs), to analyse historical pipeline failure data from 1970 to 2023. By analysing records from the US Pipeline & Hazardous Materials Safety Administration, the model captures the complexity of various degradation phenomena, predicting failure years and hazard frequencies beyond corrosion. This innovative approach allows adopting more informed preventive measures and response strategies, offering deep insights into incident causes, consequences, and patterns. The results provide practical insights for maintenance planning, offering an estimation of periods when a pipeline may be more susceptible to incidents based on various factors. However, since all models inherently present uncertainties, both in the data and the modelling process, these estimates should be interpreted as probabilistic assessments. This study provides operators with a strategic framework to prescriptively address potential vulnerabilities, thereby promoting sustained operational integrity and minimising the occurrence of unexpected events throughout the service life of pipelines. By expanding the scope of risk assessment beyond corrosion, this study significantly advances the field of pipeline safety and reliability, setting a new standard for comprehensive incident prevention.

Studies on ratcheting fatigue life prediction of 1Cr18Ni10Ti pressure pipe considering in-service loadings

Ratcheting behavior of aero-engine pressure pipe subjected to in-service loadings, including bolts preload, cyclic bending force, and internal fluid pressure, has been rarely incorporated in open experimental research. An optimized fatigue testing system was constructed to overcome the challenge caused by the non-standardized shape of the pipe. The objective of this paper is to investigate the ratcheting behavior of 1Cr18Ni10Ti pressure pipe subjected to in-service loadings and establish the ratcheting fatigue life prediction model based on the strain approach. Firstly, the effects of cyclic bending force amplitude and internal fluid pressure on the ratcheting behavior of the pressure pipe subjected to in-service loadings were analyzed. The results highlight that increasing force amplitude and internal fluid pressure lead to a remarkable ratcheting effect and shortened fatigue life. Then, the strain-based ratcheting fatigue life prediction model of the pressure pipe considering in-service loadings was developed based on finite element analysis (FEM). The main novelty of this method is that the model parameters were innovatively determined by incorporating the effects of cyclic bending force amplitude and internal fluid pressure. Lastly, the application boundary of the ratcheting fatigue life prediction method was compared by employing the KTA/ASME code, RCC-MR code, and C-TDF rule, confirming the effectiveness and feasibility of the proposed C-TDF rule. These findings advance our comprehensive understanding of the fatigue properties of the aero-engine pressure pipe considering in-service loadings.

Experimental Assessment of Corrosion Properties for Materials Intended for Heavy Crude Processing.

Heavy crude oil processing presents significant challenges owing to its complex composition and requirement for processing conditions, which increase the process safety risk in crude processing units, such as fixed equipment, for instance pressure vessels and pipes. The aim of this work is to evaluate the influence of heavy crude oils named A and B and the effect of sulfur-rich compounds and organic acids on the performance at high temperatures of three metallic alloys (5Cr-1/2Mo/ASTM A335GP5, X6CrNiMoTi17122/AISI-SAE 316Ti and Ni66.5Cu31.5/Monel 400) and propose an alternative to be used in pressure vessels and piping in refineries. This work was based on the need to understand the corrosivity of two heavy crude oils (A and B) from eastern Colombia in three materials, evaluated at three temperatures (200 °C, 250 °C and 300 °C) under the same conditions of pressure (200 psi) and rotation velocity (600 rpm) in a dynamic autoclave to simulate atmospheric conditions and conditions in vacuum refinery towers. An understanding of how these factors interact with the fundamental principles of corrosion kinetics is essential for developing an effective corrosion mitigation strategy. The results were interesting for applications requiring high corrosion resistance. X6CrNiMoTi17122/AISI-SAE 316Ti is a solid candidate for this application, with corrosion rates of 0.2 to 0.87 mpy. Ni66.5Cu31.5/Monel 400 exhibited significant corrosion rates up to 74.89 mpy, especially at higher temperatures (300 °C). 5Cr-1/2Mo/ASTM A335GP5 showed a generally moderate corrosion rate (2.04-5.57 mpy) in the evaluated temperature range.

Towards Regulations of Decommissioning Exhausted Water and Sewer Pipelines with Residues

The article provides a justification for the need to develop requirements for hydraulic characteristics of water and sewer pipes with internal deposits, that are absent in current regulations. The absence of such requirements leads to a change in the actual inner pipe diameter, flow rate and pressure losses, higher energy consumption of the pumping equipment.Purpose: To develop quantitative requirements for residue layer thickness on the inner surface of exhausted water and sewer pipes to substantiate their decommissioning.Methodology/approach: The quantitative method is used to assess the pipe operation efficiency according to the hydraulic criterion with the analysis of their hydraulic potential.Research findings: Quantitative values are proposed for the operational efficiency of exhausted pipelines according to which the residual pipe operation is determined to justify their decommissioning. Research findings will allow organizations to make decisions on decommission of exhausted engineering networks.Value: The developed proposals can be introduced in construction rules 31.13330.2021 and 32.13330.2018, justifying the need to decommission exhausted water and sewer pipelines with residues.

Building Sustainable Pipelines With a New Standard for Concrete Pressure Pipe Installation

Building Sustainable Pipelines With a New Standard for Concrete Pressure Pipe Installation

Synchronization Optimization of Pipeline Layout and Pipe Diameter Selection in a Drip Irrigation Network System Based on the Jaya Algorithm

To address the complexity and high computational burden in the design of drip irrigation networks, the Jaya algorithm is utilized to study factors affecting project costs, including equipment and pipeline depreciation and the operation and management costs of the irrigation area. A mathematical model of synchronization optimal design of pipe layout and pipe diameter selection in a drip irrigation network system with constraints on pipe diameter, flow velocity, and pipe pressure is established. Using an irrigation district in Xinjiang, China, as an example, the Jaya algorithm optimization design program was run independently 50 times, and the relative deviation of each optimization result from the optimal solution was calculated. The results show that the annual cost per unit area o is reduced to 635.99 RMB/hm2, a 25.34% reduction compared to the original engineering program, and the investment-saving effect is obvious. The relative deviation is controlled within 3%, which shows that the algorithm has stable convergence performance and can meet the requirements of actual engineering design. The Jaya algorithm eliminates the need for parameter tuning, and it excels in cost savings, algorithm stability, and computational accuracy, making it an effective method for the single-objective optimization design of drip irrigation networks.

Study on corrosion behavior of impeller of oil pump with CO2 crude oil

Abstract CO2 was one of the key factors that caused serious corrosion of petroleum equipment and facilities. Aiming to address the problem of serious pitting corrosion in the impeller of an oil pump in a CO2 flooding field, immersion, and electrochemistry experiments were comprehensively analyzed in this paper. The results showed that the corrosion rate of FV520B steel increased exponentially with the increase of pipeline transport pressure and flow rate (R2>0.9), and the potential shifted negatively. With the increase of pipe pressure, the corrosion directivity of the specimen surface gradually disappeared, showing a distinct pitting area and a comprehensive corrosion area. This was due to cavitation under high pipe pressure conditions.

Instability mechanism and vibration performance of a pumped storage power station under runaway conditions

With the large-scale access of renewable energy to the grid, the load rejection of pumped storage power stations (PSPSs) has become increasingly frequent, thus increasing the possibility of runaway accidents. This study aimed to investigate the instability mechanism and vibration performance of a PSPS by considering the coupling effect of the pressurized pipe and pump-turbine under the runaway condition. First, models of the PSPS based on the elastic water-column (elastic model) and rigid water-column (rigid model) were established. Subsequently, the vibration performances of the elastic and rigid models were compared. The comparison revealed that the runaway instability characteristics of the PSPS were mainly manifested as a high-frequency and large-amplitude vibration caused by the elastic water-column, which was not observed in the rigid model. Therefore, the elasticity of the water-column, which has normally been neglected or simplified using a rigid water-column in previous studies, has a significant effect on the runaway stability. Finally, the effects of other factors on the stability and vibration performance were clarified. The runaway stability was mainly determined by the characteristics of the runaway operating point. The discharge-head relationship coefficient (S5) for quantifying the stability performance of the runaway operating point was extracted. Moreover, increasing pipe friction loss could suppress runaway instability. Additionally, the pipe water inertia only affected the runaway vibration performance but not the runaway stability result. Overall, the study findings deepen the understanding of the physical nature of runaway instability and provide guidance for pump-turbine runner design and stable operation of PSPSs.

Identification of flange specification in real industrial settings with human reasoning assisted by augmented reality

Flange is an important component that connects pressure pipes in livelihood and industrial facilities. The specification information for a flange installed a long time ago is often unavailable or was never recorded. Precision measurement for determining the specification requires detaching the flange from connecting pipes, thus interrupting the facility’s operation. Computer vision techniques cannot guarantee reliable results for mounted flanges that are partially occluded or damaged in real environments. This study develops a new solution, augmented reality (AR)-based recognizer of flange specification (ARFS), to overcome these difficulties. This solution combines human spatial reasoning and computational intelligence in AR to distinguish multiple flanges of similar sizes in complex and uncertain on-site situations. We conducted evaluation experiments to design user interfaces for measuring key flange dimensions in AR. A usability test compares the measuring time and accuracy of the solution implemented on a handheld versus a head-mounted display device. Real-world testing confirms that deploying ARFS as a smartphone app provides an economic yet effective tool for smart asset management in the construction and infrastructure industries.

Research and Application of Flexible Fracturing Manifold in Volumetric fracturing

Abstract In order to solve the problems of high pressure pipe valves in Volumetrictric fracturing, such as large demand of high pressure pipe and valve parts, high pressure manifold for fracturing complex connection, fracturing pipeline connections are complex, long fracturing construction preparation period. The economy and timeliness of pipeline connection seriously affect the speed and efficiency of Volumetrictric fracturing operations. This paper designed and developed the high pressure flexible composite pipe and carried out its performance evaluation test. Combined with Volumetrictric fracturing operation conditions, supporting functional modular manifold system, overcome flexible pipeline and rigid pipeline fast connection technology, flexible fracturing manifold system was formed. Through the large-scale field application in the unconventional reservoir Volumetric fracturing field, The flexible fracturing manifold is compared with the conventional high-pressure pipe valve connection and the single pipe universal connection, the flexible fracturing manifold can reduce the use of high-pressure pipe valves by 1/3, increase the efficiency of fracturing manifold connection by 50%, and reduce the labor intensity by 50%, enables efficient, reduce high pressure manifold connection points by 70%. The timeliness and safety of fracturing manifold connections have been greatly improved. Flexible fracturing manifold fundamentally change the connection mode of Volumetrictric fracturing high-pressure manifold, and realizes the speed and efficiency of reservoir transformation.

Analysis of the influence of brake pipe pressure gradient on heavy haul combined train and optimisation of operation strategy

In this paper, based on the theory of gas flow, the action logic of the control valve, and the principle of multi-rigid-body dynamics, a simulation model of the 20,000 t heavy haul combined train is established to investigate the influence of brake pipe pressure gradient on the braking performance, longitudinal dynamics, braking and release characteristics of trains. Utilizing real railway line conditions, locomotive and vehicle parameters, and train operation monitoring equipment (LKJ) record data of Shuozhou-Huanghua Railway, the cyclic braking condition of the train on the long and steep downhill is simulated, and the control strategy of reducing the coupler force during the cyclic braking is proposed. The results indicate that a larger brake pipe pressure gradient before braking leads to weaker braking capability, and higher coupler forces during braking, but smaller coupler forces during release. As the brake pipe pressure gradient before braking increases, braking synchronicity decreases, while release synchronicity slightly improves. By adjusting the locomotive’s electric braking force during the cyclic braking, it is possible to appropriately increase the brake pipe pressure gradient before braking, effectively reducing coupler forces during release and reducing the number of braking cycles, thus lowering the operational difficulty of the train.

Prediction of Backward Erosion, Pipe Formation and Induced Failure Using a Multi‐Physics SPH Computational Framework

ABSTRACTSeepage‐induced backward erosion is a complex and significant issue in geotechnical engineering that threatens the stability of infrastructure. Numerical prediction of the full development of backward erosion, pipe formation and induced failure remains challenging. For the first time, this study addresses this issue by modifying a recently developed five‐phase smoothed particle hydrodynamics (SPH) erosion framework. Full development of backward erosion was subsequently analysed in a rigid flume test and a field‐scale backward erosion‐induced levee failure test. The seepage and erosion analysis provided results consistent with experimental data, including pore water pressure evolution, pipe length and water flux at the exit, demonstrating the good performance of the proposed numerical approach. Key factors influencing backward erosion, such as anisotropic flow and critical hydraulic gradient, are also investigated through a parametric study conducted with the rigid flume test. The results provide a better understanding of the mechanism of backward erosion, pipe formation and the induced post‐failure process.

Control of deposits on pipeline systems by the method of free oscillations

RELEVANCE. There are a large number of heat exchangers in operation enterprises that operate under various temperature conditions. Steam, hot water, heated products of oil refining and other industries, which may contain oxides of iron, aluminum, calcium sulfate silicates, etc., are used as a heating agent. The efficiency of the heat exchange equipment depends on the condition of the heating surfaces. Contamination of these surfaces with various deposits dramatically reduces the heat transfer coefficient, which leads to a significant increase in heat consumption. The nature of the deposits depends on the properties of the heating agent and the heated medium.THE PURPOSE. The purpose is to assess the possibility of controlling deposits on the surfaces of heat exchange equipment by the free oscillation method. The presence of deposits changes the mass of structures and, consequently, the natural frequencies of vibrations, the analysis of which can determine not only the presence and thickness of deposits, as well as their appearance.METHODS. The paper shows the results of experimental studies conducted using a hardware and software package and calculations of natural vibrations of the surfaces of heat exchange equipment in the ANSYS software package to identify their dependence on the thickness and density of deposits. A plate, a pipe, and a pressurized pipe were modeled as heat transfer surfaces.RESULTS. The results obtained experimentally and computationally coincided, and it was concluded that the free oscillation method makes it possible to determine not only the presence of deposits on heat exchange surfaces, but their thickness and appearance.CONCLUSION. The free oscillation method can detect deposits in a timely manner and monitor their condition, which in turn will, reduce overall operating costs, increase energy efficiency and extend service life.

Evaluating the need and feasibility of micro-irrigation systems for sustainable irrigation.

Irrigation is crucial for sustainable agriculture and improving farm yields, but a significant gap exists between the irrigation potential created and its actual utilization. This gap is due to losses in canal conveyance and the inefficiency of conventional irrigation methods within canal command areas. Most modernization efforts in India focus on implementing micro-irrigation for tube well systems, addressing the problem of water table decline experienced in many districts. With this context, the present study examines the command area of Gadarjudda minor of the Upper Ganga Canal in Haridwar district, Uttarakhand, India, to assess the present state of the canal by conducting on-site surveys and feasibility of micro-irrigation by evaluating the viability of replacing minor canals with a gravity flow piped irrigation network. The evaluation involves assessing the current canal status, designing the gravity flow piped irrigation network, and conducting a social survey to determine farmers' willingness, awareness, and purchasing capacity toward adoptin of micro-irrigation systems on their farms. The study identifies high conveyance loss and poor maintenance in conventional irrigation methods, highlighting the importance of micro-irrigation in the study area. The profile of the minor canal is adequate to support gravity flow in the pipe network, with velocity and pressure head within permissible limits. A social survey revealed that 85% of farmers are willing to adopt micro-irrigation, but low purchasing capacity (36%) hampers its adoption. The study concludes that micro-irrigation is viable in the Gadarjudda minor canal command area as long as a piped irrigation network is implemented and farmers receive government subsidies and proper training.

Development of an improved limit pressure solution for shape-distorted 90o pipe bends with through-wall circumferential cracks

PurposeThis paper presents the approximate limit pressure solution for shape-imperfect and through-wall circumferential cracked (TWCC) 90° pipe bends at the intrados region. Finite element (FE) limit analysis was used to estimate the limit pressure by considering the small geometrical change effects.Design/methodology/approachThree-dimensional (3D) geometric linear FE methodology was implemented to investigate the limit pressure of structurally deformed TWCC 90° pipe bends. The material considered in the analysis is elastic perfectly plastic (EPP). The limit pressure of TWCC shape-distorted pipe bends was predicted from the corresponding internal pressure when von-Mises stress was equal to or just exceeded the material’s yield strength for all the models. The theoretical solution which was published in the literature was used to evaluate the current FE approach.FindingsOvality Co and TWCC at the intrados region caused a considerable impact on pipe bends, while the thinning? Ct produced a negligible effect and hence was not included in the analysis. With the combined effect, the bend portion of pipe bend experiences substantial influence, and the TWCC effect consequently increases with 45o, 60o and 90o crack angles and decreases the limit pressure of pipe bends. An improved closed-form empirical limit pressure solution was proposed for TWCC shape-distorted pipe bends at the intrados region.Originality/valueIn the limit pressure analysis of 90° pipe bends, the implications of structural irregularities (ovality and thinning) and TWCC have not been examined and reported.